How long does a portable power station last?

Runtime on one charge

Runtime is capacity divided by load, minus inverter losses. A 1,000 Wh station running a 100 W load is an hour of runtime only in theory; in practice the inverter costs you a few percent, and a load that surges draws more than its label.

The practical version: add up the watt-hours each device will consume over the session, then compare it to usable capacity. A station is not a fuel tank you can run to zero repeatedly without consequence, either.

Service life is a chemistry question

A battery is rated for a number of charge cycles before its capacity falls to a stated fraction — usually 80%. That rating is a vendor claim, and it varies enormously between chemistries in the data we hold.

Across the models we track, vendor-stated cycle ratings run 2,000–6,000 cycles for LiFePO4 and 500–2,500 cycles for NMC (lithium-ion). That gap, not the capacity figure, is what decides whether a unit is a five-year purchase or a ten-year one.

What shortens it in practice

None of these are dramatic on their own. Together they are the difference between reaching the rated cycle count and not getting close to it.

• Heat. Leaving a station in a hot car is the fastest way to age a battery.
• Deep discharge, repeatedly. Running to zero is harder on the cells than partial cycles.
• Charging at maximum rate in the cold.
• Storage at 100% for months on end, rather than around half charge.

Reading the claim properly

A cycle rating is only comparable when the depth of discharge is stated. "3,000 cycles" with no qualifier usually means shallow cycles to 80% capacity retention, which is not the same as 3,000 full discharges. Where a vendor publishes only a bare number, treat it as a relative signal between models rather than an absolute promise — which is exactly how our rankings use it.